revset: fix - handling in the optimizer

mercurial/revset.py

@@ -486,7 +486,7 b' def optimize(x, small):'
         smallbonus = .5
 
     op = x[0]
-    if op == '-':
+    if op == 'minus':
         return optimize(('and', x[1], ('not', x[2])), small)
     elif op == 'dagrange':
         return optimize(('and', ('func', ('symbol', 'descendants'), x[1]),